Python ast 模块，Lt() 实例源码

def undoReverse(a):
    tmp = None
    if type(a) == ast.Lt:
        tmp = ast.Gt()
    elif type(a) == ast.LtE:
        tmp = ast.GtE()
    elif type(a) == ast.Gt:
        tmp = ast.Lt()
    elif type(a) == ast.GtE:
        tmp = ast.LtE()
    else:
        return a
    transferMetaData(a, tmp)
    return tmp

# Applies special functions if they're included as metadata OR if they're specified by ID

def doCompare(op, left, right):
    """Perform the given AST comparison on the values"""
    top = type(op)
    if top == ast.Eq:
        return left == right
    elif top == ast.NotEq:
        return left != right
    elif top == ast.Lt:
        return left < right
    elif top == ast.LtE:
        return left <= right
    elif top == ast.Gt:
        return left > right
    elif top == ast.GtE:
        return left >= right
    elif top == ast.Is:
        return left is right
    elif top == ast.IsNot:
        return left is not right
    elif top == ast.In:
        return left in right
    elif top == ast.NotIn:
        return left not in right

def cmpop_str(op: ast.AST) -> str:
    if isinstance(op, ast.Eq):
        return '=='
    if isinstance(op, ast.NotEq):
        return '!='
    if isinstance(op, ast.Lt):
        return '<'
    if isinstance(op, ast.LtE):
        return '<='
    if isinstance(op, ast.Gt):
        return '>'
    if isinstance(op, ast.GtE):
        return '>='
    error(loc(op), "Invalid compare operator encountered: {0}:{1}. Check supported intrisics.".format(op.lineno, op.col_offset))
    return 'INVALID_CMPOP'


# Parsers
# ------------------------------------------------------------------------------

def compare(self):
        left = Expr.parse_value_expr(self.expr.left, self.context)
        right = Expr.parse_value_expr(self.expr.comparators[0], self.context)
        if isinstance(self.expr.ops[0], ast.In) and \
           isinstance(right.typ, ListType):
            if not are_units_compatible(left.typ, right.typ.subtype) and not are_units_compatible(right.typ.subtype, left.typ):
                raise TypeMismatchException("Can't use IN comparison with different types!", self.expr)
            return self.build_in_comparator()
        else:
            if not are_units_compatible(left.typ, right.typ) and not are_units_compatible(right.typ, left.typ):
                raise TypeMismatchException("Can't compare values with different units!", self.expr)
        if len(self.expr.ops) != 1:
            raise StructureException("Cannot have a comparison with more than two elements", self.expr)
        if isinstance(self.expr.ops[0], ast.Gt):
            op = 'sgt'
        elif isinstance(self.expr.ops[0], ast.GtE):
            op = 'sge'
        elif isinstance(self.expr.ops[0], ast.LtE):
            op = 'sle'
        elif isinstance(self.expr.ops[0], ast.Lt):
            op = 'slt'
        elif isinstance(self.expr.ops[0], ast.Eq):
            op = 'eq'
        elif isinstance(self.expr.ops[0], ast.NotEq):
            op = 'ne'
        else:
            raise Exception("Unsupported comparison operator")
        if not is_numeric_type(left.typ) or not is_numeric_type(right.typ):
            if op not in ('eq', 'ne'):
                raise TypeMismatchException("Invalid type for comparison op", self.expr)
        ltyp, rtyp = left.typ.typ, right.typ.typ
        if ltyp == rtyp:
            return LLLnode.from_list([op, left, right], typ='bool', pos=getpos(self.expr))
        elif ltyp == 'decimal' and rtyp == 'num':
            return LLLnode.from_list([op, left, ['mul', right, DECIMAL_DIVISOR]], typ='bool', pos=getpos(self.expr))
        elif ltyp == 'num' and rtyp == 'decimal':
            return LLLnode.from_list([op, ['mul', left, DECIMAL_DIVISOR], right], typ='bool', pos=getpos(self.expr))
        else:
            raise TypeMismatchException("Unsupported types for comparison: %r %r" % (ltyp, rtyp), self.expr)

def reverse(op):
    """Reverse the direction of the comparison for normalization purposes"""
    rev = not op.reversed if hasattr(op, "reversed") else True
    if type(op) == ast.Gt:
        newOp = ast.Lt()
        transferMetaData(op, newOp)
        newOp.reversed = rev
        return newOp
    elif type(op) == ast.GtE:
        newOp = ast.LtE()
        transferMetaData(op, newOp)
        newOp.reversed = rev
        return newOp
    else:
        return op # Do not change!

def visit_Compare(self, node):
        left_term = self.visit(node.left)
        if len(node.comparators) > 1:
            raise Exception("Cannot handle 'foo > bar > baz' comparison in %s"
                            % unparse(node))
        right_term = self.visit(node.comparators[0])
        op = node.ops[0]
        if isinstance(op, ast.Eq):
            if self.__is_bool(left_term) and self.__is_bool(right_term):
                if left_term == True:
                    return right_term
                elif right_term == True:
                    return left_term
                elif left_term == False:
                    return Not(right_term)
                elif right_term == False:
                    return Not(left_term)
            return left_term == right_term
        elif isinstance(op, ast.Lt):
            return left_term < right_term
        elif isinstance(op, ast.LtE):
            return left_term <= right_term
        elif isinstance(op, ast.Gt):
            return left_term > right_term
        elif isinstance(op, ast.GtE):
            return left_term >= right_term
        else:
            raise Exception("Unhandled operators '%s' in %s"
                            % (unparse(op), unparse(node)))

def Lt():
    return functools.partial(_compare, operator.lt)

def whereeval(str_, get=None):
    """Evaluate a set operation string, where each Name is fetched"""
    if get is None:
        import redbiom
        config = redbiom.get_config()
        get = redbiom._requests.make_get(config)

    # Load is subject to indirection to simplify testing
    globals()['Load'] = make_Load(get)

    formed = ast.parse(str_, mode='eval')

    node_types = (ast.Compare, ast.In, ast.NotIn, ast.BoolOp, ast.And,
                  ast.Name, ast.Or, ast.Eq, ast.Lt, ast.LtE, ast.Gt, ast.GtE,
                  ast.NotEq, ast.Str, ast.Num, ast.Load, ast.Expression,
                  ast.Tuple, ast.Is, ast.IsNot)

    for node in ast.walk(formed):
        if not isinstance(node, node_types):
            raise TypeError("Unsupported node type: %s" % ast.dump(node))

    result = eval(ast.dump(formed))

    # clean up
    global Load
    del Load

    return result

def Lt(self, key, right):
        c = criteria_class.instance(Const.Lt, key, right)
        self._push(c)
        return self

def __init__(self, key, right):
        super(Lt, self).__init__(key, right, operator.lt)

def mutate_Gt(self, node):
        return ast.Lt()

def mutate_LtE_to_Lt(self, node):
        return ast.Lt()

def pythonast(self, args, tonative=False):
        return ast.Compare(args[0], [ast.Lt()], [args[1]])

def syn_Compare(self, ctx, e):
        left, ops, comparators = e.left, e.ops, e.comparators
        for op in ops:
            if isinstance(op, (ast.Lt, ast.LtE, ast.Gt, ast.GtE)):
                raise _errors.TyError("No ordering relation on complex numbers.", e)
            elif isinstance(op, (ast.In, ast.NotIn)):
                raise _errors.TyError("Type complex does not support this operator.", op)
        for e_ in _util.tpl_cons(left, comparators):
            if hasattr(e_, 'match'): 
                continue # already synthesized
            ctx.ana(e_, self)
        return _boolean.boolean

def areDisjoint(a, b):
    """Are the sets of values that satisfy these two boolean constraints disjoint?"""
    # The easiest way to be disjoint is to have comparisons that cover different areas
    if type(a) == type(b) == ast.Compare:
        aop = a.ops[0]
        bop = b.ops[0]
        aLeft = a.left
        aRight = a.comparators[0]
        bLeft = b.left
        bRight = b.comparators[0]
        alblComp = compareASTs(aLeft, bLeft, checkEquality=True)
        albrComp = compareASTs(aLeft, bRight, checkEquality=True)
        arblComp = compareASTs(aRight, bLeft, checkEquality=True)
        arbrComp = compareASTs(aRight, bRight, checkEquality=True)
        altype = type(aLeft) in [ast.Num, ast.Str]
        artype = type(aRight) in [ast.Num, ast.Str]
        bltype = type(bLeft) in [ast.Num, ast.Str]
        brtype = type(bRight) in [ast.Num, ast.Str]

        if (type(aop) == ast.Eq and type(bop) == ast.NotEq) or \
            (type(bop) == ast.Eq and type(aop) == ast.NotEq):
            # x == y, x != y
            if (alblComp == 0 and arbrComp == 0) or (albrComp == 0 and arblComp == 0):
                return True
        elif type(aop) == type(bop) == ast.Eq:
            if (alblComp == 0 and arbrComp == 0) or (albrComp == 0 and arblComp == 0):
                return False
            # x = num1, x = num2
            elif alblComp == 0 and artype and brtype:
                return True
            elif albrComp == 0 and artype and bltype:
                return True
            elif arblComp == 0 and altype and brtype:
                return True
            elif arbrComp == 0 and altype and bltype:
                return True
        elif (type(aop) == ast.Lt and type(bop) == ast.GtE) or \
            (type(aop) == ast.Gt and type(bop) == ast.LtE) or \
            (type(aop) == ast.LtE and type(bop) == ast.Gt) or \
            (type(aop) == ast.GtE and type(bop) == ast.Lt) or \
            (type(aop) == ast.Is and type(bop) == ast.IsNot) or \
            (type(aop) == ast.IsNot and type(bop) == ast.Is) or \
            (type(aop) == ast.In and type(bop) == ast.NotIn) or \
            (type(aop) == ast.NotIn and type(bop) == ast.In):
            if alblComp == 0 and arbrComp == 0:
                return True
        elif (type(aop) == ast.Lt and type(bop) == ast.LtE) or \
            (type(aop) == ast.Gt and type(bop) == ast.GtE) or \
            (type(aop) == ast.LtE and type(bop) == ast.Lt) or \
            (type(aop) == ast.GtE and type(bop) == ast.Gt):
            if albrComp == 0 and arblComp == 0:
                return True
    elif type(a) == type(b) == ast.BoolOp:
        return False # for now- TODO: when is this not true?
    elif type(a) == ast.UnaryOp and type(a.op) == ast.Not:
        if compareASTs(a.operand, b, checkEquality=True) == 0:
            return True
    elif type(b) == ast.UnaryOp and type(b.op) == ast.Not:
        if compareASTs(b.operand, a, checkEquality=True) == 0:
            return True
    return False

def negate(op):
    """Return the negation of the provided operator"""
    if op == None:
        return None
    top = type(op)
    neg = not op.negated if hasattr(op, "negated") else True
    if top == ast.And:
        newOp = ast.Or()
    elif top == ast.Or:
        newOp = ast.And()
    elif top == ast.Eq:
        newOp = ast.NotEq()
    elif top == ast.NotEq:
        newOp = ast.Eq()
    elif top == ast.Lt:
        newOp = ast.GtE()
    elif top == ast.GtE:
        newOp = ast.Lt()
    elif top == ast.Gt:
        newOp = ast.LtE()
    elif top == ast.LtE:
        newOp = ast.Gt()
    elif top == ast.Is:
        newOp = ast.IsNot()
    elif top == ast.IsNot:
        newOp = ast.Is()
    elif top == ast.In:
        newOp = ast.NotIn()
    elif top == ast.NotIn:
        newOp = ast.In()
    elif top == ast.NameConstant and op.value in [True, False]:
        op.value = not op.value
        op.negated = neg
        return op
    elif top == ast.Compare:
        if len(op.ops) == 1:
            op.ops[0] = negate(op.ops[0])
            op.negated = neg
            return op
        else:
            values = []
            allOperands = [op.left] + op.comparators
            for i in range(len(op.ops)):
                values.append(ast.Compare(allOperands[i], [negate(op.ops[i])],
                                          [allOperands[i+1]], multiCompPart=True))
            newOp = ast.BoolOp(ast.Or(multiCompOp=True), values, multiComp=True)
    elif top == ast.UnaryOp and type(op.op) == ast.Not and \
            eventualType(op.operand) == bool: # this can mess things up type-wise
        return op.operand
    else:
        # this is a normal value, so put a not around it
        newOp = ast.UnaryOp(ast.Not(addedNot=True), op)
    transferMetaData(op, newOp)
    newOp.negated = neg
    return newOp